Mechanical fastener feeding assembly



United States Patent 7/1966 Maynard......................

1/1970 Novak.......................:::

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ABSTRACT: A tool for driving successive nails from a strip includes anosepiece structure forming a drive track to which nails are fed insequence from a guideway extending to a magazine. The strip is indexedthrough the guideway by a pawl assembly actuated by placing the toolagainst a workpiece. The pawl assembly includes a plate which has atoothed nail engaging portion and which is mounted for pivoting movementtoward and away from the guideway and rectilinear movement toward andaway from the guide track. An actuator reciprocated in a verticaldirection by a spring and selective engagement with the workpiececarries a pin sliding in an inclined slot in the pawl plate to actuatethe pawl assembly.

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PATENTEU UEC29 I976 SHEET 3 BF 3 e lnven/ar ALLEN R. OBERGFELLAttorneys.

MECHANICAL FASTENER FEEDING ASSEMBLY BACKGROUND OF THE INVENTION Thisinvention relates to a fastener feeding assembly and, more particularly,to'a new and improved assembly actuated by placing the tool against aworkpiece for feeding successive fasteners from a strip into the drivetrack of the tool.

Pneumatic tools for driving fasteners from strips, either flexible orrelatively rigid, have used various fastener feeding assemblies withpawls, followers, or sprockets for advancing successive nails orfasteners into a drive tracli in synchronism with the operation of thefastener driving tool. These feeding assemblies have been resiliently,pneumatically, ormechanically operated. As an example, U.S. Pat. No.3,259,292 discloses a mechanically actuated nail feeding apparatus usinga sprocket wheel indexed through successive steps by means of a drivepin rotated by placing the nosepiece of the tool on a workpiece. Thistype of drive subjects the drive pin to rather substantial torsionalstresses in dependence on the manner in which the tool is used.Accordingly, it would be desirable to provide a mechanically actuatedfeeding assembly using easily manufactured and replaced parts of adurable construction.

SUMMARY OF THE INVENTiON- A mechanically actuated fastener feedingassembly for use with a pneumatically actuated fastener driving too] andembodying the present invention includes the housing for the tool and anosepiece structure both defining a drive-track and having a lower endadapted to be placed adjacent the workpiece into which the fastener ornail is to be driven. The nosepiece structure also includes a projectingstructure defining a portion of a guideway opening into the drive track,and the fastener feeding assembly is mounted on the nosepiece struc:ture to complete the definition of the guideway. A platelike pawlmounted in a recessed wall of the assembly includes a toothed nail shankengaging portion offset from the plane of the pawl and extending throughan elongated opening into the guideway. The pawl is mounted in therecess for rectilinear movement toward and away from the drive track andpivoting movement toward and away from the guideway with a springnormally biasing the toothed portion of the pawl into engagement withthe shanks of the nails in a strip disposed in the guideway. The pawlassembly is actuated by an assembly including a generally flat platemounted for reciprocating movement generally parallel to the pawl andhaving a portion surrounding and projecting below the lower end of thenosepiece structure. A pin carried on the actuator plate is slidablyreceived within an inclined slot formed in the pawl.

When the tool is positioned against a workpiece, the actuator movesvertically and elevates the pin which cooperates with the slot in thepawl to retract or slide the pawl in a direction away from theworkpiece. During this movement, the pawl is pivoted against the springto move the toothed portion out of engagement with one set of nails andthen back into engagement with a new set of nails to prepare the stripfor being advanced to feed the next nail into the drive track. After thetool has been operated to drive the nailthen in the drive track and thetool is lifted from engagement with the work- BRIEF DESCRIPTION OF THEDRAWINGS Many other objects and advantages of the present invention willbecome apparent from considering the following detailed description inconjunction with the drawings in which:

FIG. 1 is an elevational view of a mechanically actuated nail feedingassembly embodying the present invention;

FIG. 2 is an enlarged sectional view taken .along line 2-2 in FIG. 1;

FIG. 3 is a sectional view taken along line 3-3 in FIG. 2;

FIG. 4 is a fragmentary sectional view taken along line 4-4 in FIG. 3;

FIG. 5 is a sectional view taken along line 5-5 in FIG. 3;

FIG. 6 is a sectional view taken along line 6-6 in FIG. 2;

FIG. 7 is an exploded perspective view of a nosepiece structure for afastener driving tool and the components of the fastener feedingassembly; and

FIG. 8 is an exploded perspective viewof a pawl and pawl supportingmember included in the fastener feeding assembly and illustrated fromthe opposite side from FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now more specificallyto the drawings, therein is illustrated a fastener feeding assemblywhich embodies the present invention and which is indicated generally as10. The fastener feeding assembly 10 is adapted for use with apneumatically actuated fastener driving tool and feeds successive headedfasteners such as nails 12 (FIGS. 2 and 3) from a nail strip indicatedgenerally as 14 from a magazine indicated generally as 16 to a drivetrack 18 formed in a nosepiece structure indicated generally as 20. Thenosepiece structure 20 closes and is secured to the lower portion of ahousing 22 for the fastener driving tool. Each time that the tool isplaced against a workpiece (not shown), the assembly 10 is actuated tofeed a nail 12 from the strip 14 to the drive track 18.

Although the nail strip 14, the magazine assembly 16, and the fastenerdriving tool can be of any suitable construction, the illustrated nailstrip 14 including a generally U-shaped plastic carrier 24 for holdingthe nails 12 in spaced parallel relation is one illustrated anddescribed in detail in the copending application of George .I. Gallee etal., Ser. No. 637,510, filed may 10, 1967, now Pat. No. 3,438,487. Themagazine assembly 16 can be of any suitable type, such as the one shownand described in detail in the copending application of Allen R.Obergfell et al., Ser. No. 736,425, filed June 12, 1968, whichapplication is also assigned to the same assignee as the presentapplication. The pneumatic fastener driving tool of which the housing 22forms a part can also be of any suitable construction such as that shownin the cope nding application of Allen R. Obergfell, Ser. No. 767,020,filed Aug. 26, 1968, abandoned, which application is assigned to thesame assignee as the present application.

Referring now more specifically to the nosepiece structure 20, thisstructure includes a forward portion 20A defining the drive track 18 andterminating in agenerally cylindrical portion 208 at its lower endforming thelow er end of the drive track 18. The rearwardly extendingportion of the part 20A of the nosepiece structure 20 includes a slot 26(FIG. 7) forming an access opening to the drive track 18 that opens tothe rear of the tool. The nosepiece structure 20 also includes arearwardly extending wall portion 20C (FIG. 7) which defines one half ofa guideway for feeding the strip '14 from the magazine assembly 16 tothe drive track 18, which guideway is indicated generally as 28. Asillustrated in FIG. 3, the rearwardly extending wall portion 20Cincludes a recess 30 for accommodating the U-shaped flexible carrier 24and another recess 32.

The definition of the guideway 28 is completed by a pair of wall members34 and 36 (FIGS. 3 and 7) which are disposed in generally parallelrelationship with respect to each other with the right-hand portion ofthe wall member 34 (FIG. 3) disposed in an adjacent relation to the wallportion 20C of the nosepiece structure 20 to completethe definition ofthe guideway 28. The wall members 34 and. 36 are secured together in anabutting relation by a pair of threaded fasteners .or machine screws 38,and the wall member 36 is secured to as 42 is secured to the nosepiecestructure 20 as by a plurality.

of threaded fasteners 44 (FIGS. 1, 2, and 5) to provide a continuationof the guideway 28 for guiding the spent portion of the nail stripcarrier 24 forwardly of the drive track 18 after the nails 12 have beenremoved therefrom and driven into a workpiece.

To provide means for feeding the nail strip 14, the assembly includes apawl indicated generally as 50 having a central and generally verticallyextending flat wall portion 50A (FIG. 7), a rounded or arcuate lower endportion 508, and an offset or transversely extending toothed portion 50Cat its upper end. The pawl 50 is mounted in a recess 52 formed in anouter surface of the wall member 34 with the toothed portion 50Cextending through an elongated opening 54 in the wall 34 (FIGS. 7 and 8)to be coupled with the shanks of the nails 12. The arcuate or roundedportion 503 of the pawl 50 is slidably and pivotally mounted on asurface 34A (FIGS. 3, 5, and 6) of the wall member 34.

To provide means for resiliently biasing the toothed portion 50C of thepawl 50 into a coupled relation with the shanks of the nails 12, thereis provided a spring member indicated generally as 56 (FIG. 7) having acoiled portion 56A and an upper arm portion 56B. The spring 56 ismounted on the wall member 34 by an elongated threaded fastener 58 whichpasses through a bore or opening 60 in the wall member 34 with anintermediate portion of the fastener 58 passing through the coiledportion 56A. When so mounted on the wall member 34, the coiled portion56A is disposed within a recess or slot 62 in the wall 34 with thetransversely extending arm 56B bearing against the vertical wall portion50A of the pawl member 50in sliding engagement therewith (see FIGS. 2,3, 5, and 6). The spring 56 pivots the pawl 50 about the lower roundedportion 508 in a clockwise direction (FIG. 3) to force the toothedportion 50C through the opening 54 and into a coupled engagement withthe shanks of the nails 12 disposed adjacent the pawl 50 in the guideway28.

To provide means for operating the pawl 50, an actuating means indicatedgenerally as 66 is provided having an upper flat or plate portion 66Aslidably mounted in a recess 68 formed on an inner surface of the wallmember 36. The actuating means 66 includes a lower and semicylindricalportion 66B which partially encircles and is normally disposed beneaththe cylindrical portion 203 on the nosepiece structure (FIGS. 1, 3, and5). The actuating member 66 is normally resiliently biased to theposition illustrated in FIGS. 1, 3, and 5 by a pair of compressionsprings 70 which are disposed in a pair of downwardly facing openings 72in the lower edge of the wall member 36. The upper end of each of thecompression springs 70 bears against the endwall defining the upper endof each of the openings 72, and the lower ends of each of the springs 70bear against a pair of flanges or tabs 66C struck out-of the verticalwall 66A of the actuator 66. The tabs 66C extend through slots 74 formedin the lower edge of the wall member 66 aligned with the openings 72.The actuator 66 is coupled to the pawl 50 by a pin 76 which is securedto the flat wall 66A and is slidably received within a slot 78 formed inthe vertical wall portion 50A of the pawl 50, the wall portions 50Aand'66A being disposed generally parallel to each other and to theguideway 28 (FIG. 3).

'To prevent retrograde or reverse movement of the strip 14 duringoperation of the feeding assembly 10, a resilient locking pawl 80including a toothed portion 80A is disposed in the'opening or recess 32in the Wall 20C of the nosepiece structure 20 and is secured therein bya pair of fasteners such as a pair of rivets 82 (FIGS. 3, 4, and 7). Thetoothed portion 80A of the detent or pawl 80 projects into the guideway28 generally opposite but somewhat below the toothed portion 50C on thepawl 50 to engage the shanks of a set of nails in the strip 14. Thetoothed portion 80A is so formed that the pawl or'detent 80 is cammed tothe right (FIG. 3) when the strip is moved to the left (FIG. 5) butprevents movement of the nail strip 14 to the right (FIG. 5).

When the tool of which the fastener feeding assembly 10 forms a part isto be operated, a pivoted front cover 16B on the magazine assembly 16 isopened and a rolled fastener containing strip 14 is disposed within themagazine 16. The leading edge of the strip 14 is advanced to theposition shown in FIG. 2 by feeding the strip through the guideway 28 sothat the v first nail 12 in the strip 14 is disposed in the drive track.18 The cover 16B is then closed, and the tool is prepared operation.

When the tool is to be operated, the workpiece engagi i'igi portion 66Bof the actuator is placed against the workpiece. The tool is thendepressed so that theactuator 66 moves upwardly against the compressiveforce of the springs 70. If desired, the actuator 66 can be coupled to asafety or touch-. trip mechanism of the type disclosed in theabove-identified Obergfell application which is-cornbined with a triggercontrol,

to provide an interlock by which the tool cannot be operated unless thelower end of the drive track defining'portion 20B of the nosepiecestructure 20 is placed against the workpiece.

When the tool is thus operated or controlled, a driver blade directionof movement of the nails 12, the pin 76 bears against the upper edge ofthe portion of the flat wall 50A of the pawl 50 defining the slot 78 tocam the pawl 50 to the right from the position shown in solid outline inFIG. 5 to the position shown in dot-and-dash outline in FIG. 5. Duringthis movement, the arcuate lower end portion 50B of the pawl 50 slidesalong the surface 34A. During this movement, the toothed portion 50C onthe pawl cams against the shanks of the nails 12 in the guideway 28 topivot the pawl 50 about the arcuate portion 503 and against the force ofthe spring 56 to the position shown in FIG. 6 so as to permit the pawl50 to move rearwardly away from the drive track 18 to the position shownin dot-and-dash outline in FIG. 5. As the pawl 50 approaches thisposition and after the separate teeth of the toothed portion 50C movepast one set of nails 12, the spring 56 pivots the pawl 50 in aclockwise direction about the rounded portion 508 to a position in whichthe toothed portion 50C is again coupled with the shanks of a set ofnails in the strip 14 in the I the actuator 66. During this movement,the pin 76 cooperates with the lower wall defining the slot 78 on thepawl 70 to impart rectilinear sliding movement toward the drive track 18from the right-hand position shown in dot-and-dash outline in 7 FIG. 5to the position shown in solid line therein. During this movement, thepawl 50 advances the strip 14 a single step so that the next nail 12 isnow disposed beneath the lower end of the driving element 90 within thedrive track 18. The forward end of the carrier 24 from which the nailhas been driven is advanced into the guideway structure 42. In thismanner, a nail 12 is advanced into the drive track 18 each time that thenosepiece structure 20 of the tool is placed adjacent a workpiece.

Although the pawl 50 is illustrated as engaging the nails 12 to feed thestrip 14 toward the drive track, this pawl can engage the carrier 24 tofeed the strip 14 by merely placing the feeding assembly on the oppositeside of the guideway 28.

Iclaim:

1. In a tool for driving fasteners into a workpiece from a strip ofspaced fasteners:

structure defining a drive track and having a lower end adapted to bedisposed adjacent the workpiece;

a magazine assembly for receiving a strip of fasteners and having aguideway leading into the drive track through which the strip extends;

pawl means mounted for pivoting and reciprocating movement, said pawlmeans being adapted to engage the fastener strip in said guideway; aworkpiece engaging means movably mounted adjacent said lower end andadapted to engage the workpiece; and means coupling the workpieceengaging means to the pawl means so that movement of the workpieceengaging means imparts pivotal and reciprocating movement to the pawlmeans to feed the fastener strip through said guideway toward the drivetrack. 2. In a tool for driving a fastener from a strip of spacedfasteners into a workpiece: structure defining a drive track and havinga lower end adapted to be disposed adjacent the workpiece, saidstructurealso defining a guideway leading into the drive track adapted to receivea strip of fasteners, said structure also forming a recessed areacommunicating with the guideway;

pawl means disposed in said recessed area and resiliently biased intoengagement with a fastener in the guideway, said pawl means beingmounted for pivoting movement toward and away from the fastener in theguideway and for reciprocating movement in a direction parallel to theguideway;

movably mounted actuating means adapted to engage the workpiece andincluding a portion mounted for reciprocating movement in a directiongenerally parallel to the drive track; and

means coupling the pawl means and said portion of the actuating means toreciprocate the pawl means in response to reciprocation of said portion,the. reciprocation of the pawl means advancing the fastener strip in theguideway and pivoting the pawl means in opposite directions to couplethe pawl means to successive ones of the fasteners.

3. In a tool for driving a fastener from astrip of spaced fasteners intoa workpiece:

structure defining a drive track and having a lower end adapted to bedisposed adjacent the workpiece, said structure also defining aguideway. leading into the drive track adapted to receive astrip offasteners, said structure also forming a recessed area communicatingwith the guideway;

a pawl member disposed in transversely extending toothed portion, saidpawl member being mounted for pivotal movement toward and away from theguideway and for reciprocating movement parallel to the guideway;

resilient means biasing the toothed portion into engagement with thefastener strip in the guideway;

an actuating assembly operated by engagement with the workpiece andincluding an actuating member mounted adjacent the pawl member forreciprocating movement in a direction transverse to the direction ofmovement of the fastener through the guideway; and

coupling means coupling the pawl and actuating members and including apin on one of the members and an inclined slot in the other of themembers for reciprocating the pawl member in response to reciprocationof the actuating member, reciprocation of the pawl member feeding thefasteners toward the drive track and pivoting the toothed portion intoand out of coupled relation with the fastener strip. v

4. In a tool for driving fasteners into a workpiece from a strip ofspaced fasteners:

structure defining a drive track and a portion of a strip guidewaycommunicating with the drive track;

an assembly mounted on the structure and including a wall membercooperating with the structure to complete the definition of the stripguideway, said wall member providing an elongated opening communicatingwith the guideway;

pawl means mounted on said wall member for reciprocating said recessedarea and having amovement generally parallel to the guideway and towardand away from the drive track, said pawl means having a toothed portionextending through the elongated opening to engage the fastener strip inthe guideway; and

actuating means coupled to the pawl'means and actuated by engagementwith the workpiece for actuating the pawl means.

5. The tool set forth in claim 4 in which:

the wall member includes a recessed area communicating with theelongated opening and spaced away from the guideway; and

the pawl means includes a generally flat plate portion disposed in therecessed area and having the toothed portion extending into saidelongated opening substantially perpendicular to the flat plate portion.

6. The tool set forth in claim 5 in which, the actuating means includesa flat plate portion at least partially closing the recessed area andmounted for rectilinear movement in a direction transverse to thedirection of reciprocating movement of the pawl means.

7. The tool set forth in claim 6 in which, the flat plate portion of theactuating means and the pawl means are coupled together by a pinslidable within an inclined slot.

8. The tool set forth in claim 6 in which:

the structure includes a lower and portion adapted to be disposedadjacent the workpiece; and

the actuating means includes a workpiece engaging portion at leastpartially surrounding the lower end portion and coupled to the flatplate portion of the actuating means.

9. The tool set forth in claim 8 including, resilient means normallybiasing the workpiece engaging portion of the actuating means to aposition projecting beyond the lower end portion of the structure.

10. In a tool for driving a fastener from a strip of spaced fastenersinto a workpiece:

structure defining a drive track and having a lower end adapted to bedisposed adjacent. the workpiece, said structure also defining aguideway leading into the drive track adapted to receive a strip offasteners, said structure also defining an opening extending generallyparallel to the guideway and communicating with the guideway through anelongated slot;

a pawl member mounted for sliding and pivoting movement in the openingand including a toothed portion extending through the slot to engage thefastener strip in the guideway;'

first biasing means acting on the pawl member for biasing the toothedportion into coupled'engagement with the fastener strip;

an actuating member disposed adjacent the pawl member;

coupling means including a pin and an inclined slot on the actuating andpawl members for coupling these members;

means actuated by engagement with the workpiece for impartingrectilinear movement in a first direction to the actuating member tomove the coupled pawl member in a direction away from the drive track,the pawl member being pivoted out of coupled engagement with thefastener strip and then being pivoted back into engagement with thefastener strip spaced away from the drive track a distance of onefastener by the first biasing means during the movement of the pawlmember in said first direction; and second biasing means acting on theactuating member for imparting rectilinear movement to the actuatingmember in a second direction opposite tothe first direction to move thepawl member in a second direction toward the drive track so that thetoothed portion feeds the fasteners toward the drive track. 11. The toolset forth in claim 1 including mounting structure engaging said pawlmeans to cause reciprocating movement of said pawl means to besubstantially rectilinear.

